Actuators are used to convert electronic signals into mechanical motion. In many applications such as, for example, portable devices, imaging related devices, telecommunications components, and medical instruments, it may be beneficial for miniature actuators to fit within the small size, low power, and cost constraints of the application.
Micro-electrical-mechanical system (MEMS) technology is the technology that in its most general form can be defined as miniaturized mechanical and electro-mechanical elements that are made using the techniques of microfabrication. The critical dimensions of MEMS devices can vary from well below one micron to several millimeters. In general, MEMS actuators are more compact than conventional actuators, and they consume less power.
In some applications, such as moving an image sensor in a camera for automatic focusing (AF) or optical image stabilization (OIS), an actuator is used to move an optoelectronic device that has a number of electrical inputs and outputs. For example, European patent No. EP 0253375, entitled “Two-Dimensional Piezoelectric Actuator,” by Fukada et al., teaches a design for a two-dimensional actuator that can be used to move an image sensor in a plane. The actuator taught by Fukada, however, is large and unamenable to space-constrained applications. For example, Fukuda's actuator may be used in large, stand-alone digital cameras due to the associated space constraints of other, smaller devices.
Unlike conventional actuators, MEMS actuators may be used to, for example, move or position certain passive components within miniature cell phone cameras. By way of example, U.S. Pat. No. 8,604,663, entitled “Motion controlled actuator,” and U.S. Patent Application Publication No. 2013/0077945 A1, entitled “Mems-Based Optical Image Stabilization,” teaches MEMS actuators for moving a lens in a miniature camera (e.g., for use in a cell phone). However, neither of these MEMS actuators is able to move an optoelectronic device that has a number of electrical inputs and outputs. In addition, both of these MEMS actuators utilize deployment mechanisms that add complexity, size, and cost.